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United States Patent |
6,098,131
|
Unger
,   et al.
|
August 1, 2000
|
Network apparatus with removable electronic module
Abstract
A network apparatus having a chassis with an external network data port and
a removable electronic module coupled to the network data port through an
internal data port when the removable electronic module is present in the
chassis. The chassis may also provide power, radio frequency (RF), data
bus, and other types of electrical and data connections to the electronic
module through the use of additional internal ports. The apparatus may
additionally be connected to others via a data bus, and be included as
part of a rack-mounted system. The electronic module may be inserted and
removed from the chassis while electrical power is applied to the chassis.
Inventors:
|
Unger; Dave (Windham, NH);
Berman; David J. (Swampscott, MA);
Grobicki; Christopher (Andover, MA);
McNally; Lance J. (Townsend, MA);
Shufelt; Mark (Salem, NH);
Ulm; John (Pepperell, MA)
|
Assignee:
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Nortel Networks Limited (Montreal, CA)
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Appl. No.:
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072410 |
Filed:
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May 4, 1998 |
Current U.S. Class: |
710/303; 361/683; 361/686; 361/687 |
Intern'l Class: |
G06F 013/14 |
Field of Search: |
710/101,102,103
361/683,686,687
|
References Cited
U.S. Patent Documents
5471474 | Nov., 1995 | Grobicki et al. | 370/85.
|
5477415 | Dec., 1995 | Mitcham et al. | 361/686.
|
5619398 | Apr., 1997 | Harrison et al. | 361/686.
|
5684673 | Nov., 1997 | Shibasaki et al. | 361/686.
|
5784253 | Jul., 1998 | Ooka et al. | 361/686.
|
5816673 | Oct., 1998 | Sauer et al. | 312/223.
|
5875094 | Feb., 1999 | Kirkendoll | 361/686.
|
5926627 | Jul., 1999 | Sugimura | 395/281.
|
5933321 | Aug., 1999 | Ruch et al. | 361/686.
|
5941965 | Aug., 1999 | Moroz et al. | 710/101.
|
Other References
"Data-Over-Cable Service Interface Specifications", Radio Frequency
Interface Specification, 1997, Cable Television Laboratories, Inc.
|
Primary Examiner: Lee; Thomas C.
Assistant Examiner: Elamin; Abdelmoniem
Attorney, Agent or Firm: Blakely Sokoloff Taylor & Zafman LLP
Claims
What is claimed is:
1. A network apparatus comprising:
a chassis having an external network data port at each of a plurality of
positions;
an internal network data port coupled to the external network data port; a
plurality of external radio frequency (RF) connectors coupled to the
chassis at each of the plurality of positions;
a plurality of internal RF connectors, each of the plurality of internal RF
connectors coupled to one of the plurality of external RF connectors; and
a removable electronic module having a module network data port
electronically coupled to the internal network data port and a plurality
of module RF connectors electrically coupled to the plurality of internal
RF connectors when the removable electronic module is present in the
chassis at one of the plurality of positions.
2. The apparatus of claim 1 wherein the electronic module comprises a
distal edge and a proximal edge, the module data port and the plurality of
module RF connectors are located substantially along the proximal edge.
3. The apparatus of claim 2 further comprising:
one or more power supply modules coupled to the chassis;
a plurality of internal power connectors coupled to the one or more power
supply modules; and
a module power connector coupled to the electronic module, wherein the
module power connector is electrically coupled to one of the plurality of
internal power connectors when the removable electronic module is present
in the chassis at one of the plurality of positions.
4. The apparatus of claim 3 wherein the module power connector is located
substantially along the proximal edge of the electronic module.
5. The apparatus of claim 2 further comprising:
an internal data bus connector coupled to the chassis; and
a module data bus connector coupled to the electronic module, wherein the
module data bus connector is electrically coupled to the internal data bus
connector when the removable electronic module is present in the chassis,
the module data bus connector located substantially along the proximal
edge of the electronic module.
6. The apparatus of claim 2 further comprising an electronic display
coupled to the electronic module substantially along the distal edge of
the electronic module.
7. The apparatus of claim 1 wherein the electronic module may be inserted
and removed from the chassis while electrical power is applied to the
chassis.
8. A method for scaling a head end in a data-over-cable service network,
the method comprising:
connecting a plurality of head-end coaxial cables to a plurality of
external radio frequency (RF) connectors at one of a plurality of
positions on a chassis, each of the plurality of external RF connectors
being coupled to one of a plurality of internal RF ports;
connecting an external network connection to an external network data port
at the one of the plurality of positions on the chassis, the external
network data port being coupled to an internal network port; and
inserting an electronic module at the one of the plurality of positions on
the chassis, the electronic module having a plurality of module RF ports
and a module network port, the insertion coupling the plurality of module
RF ports to the plurality of internal RF ports and coupling the module
network port to the internal network port, thereby incrementally
increasing the scale of the data-over-cable service network provided by
the head-end.
9. The method of claim 8, further comprising:
removing the electronic module from the one of the plurality of positions
on the chassis, the removal uncoupling the plurality of module RF ports
from the plurality of internal RF ports and uncoupling the module network
port from the internal network port, thereby incrementally decreasing the
scale of the data-over-cable service network provided by the head-end.
10. The method of claim 8, further comprising:
removing the electronic module from the one of the plurality of positions
on the chassis; and
inserting a second module at the one of the plurality of positions on the
chassis, the second module having a second plurality of module RF ports
and a second module network port, the insertion coupling the second
plurality of module RF ports to the plurality of internal RF ports and
coupling the second module network port to the internal network port,
thereby maintaining the scale of the data-over-cable service network
provided by the head-end.
Description
FIELD OF THE INVENTION
This invention relates generally to data communications networks, and more
particularly, to a network apparatus having a chassis with multiple
external network ports and a removable electronic module coupled to the
network ports through an internal port when the removable electronic
module is present in the chassis.
BACKGROUND OF THE INVENTION
Community-antenna television (CATV), often referred to simply as cable TV,
uses coaxial cable to distribute standard television signals to customers
receiving the service. Generally, CATV systems are accessed by greater
numbers of users than access either local area network (LAN) or
metropolitan area network (MAN) systems. CATV systems typically include a
head end at which signals that are received from the source of programming
material are processed for transmission over the system, a trunk system,
which is the main artery carrying the processed signals, a distribution
system, which is a bridge from the trunk system lines and carries signals
to subscriber areas, and subscriber drops, which are fed from taps on the
distribution system to feed subscriber TV receivers.
In order to service the large number of subscribers positioned randomly
over the very large geographic area covered by a CATV system, the head end
has both wireless and wired connections to distribution systems or remote
head ends, which connect to yet further distribution systems. These
distribution schemes include the use of satellites.
The primary goal of CATV has been to provide high quality TV signals for
subscribers. However, today some CATV systems use optical fiber cable to
increase the number of channels that can be carried. These systems also
have some interactive communications between the subscribers and the
programming source, and between subscribers. As a result, CATV systems can
carry many more TV channels than ever before, as well as provide other
types of communications services on a limited basis.
CATV systems have a spanning tree topology. In principle, this could be
adapted to expand the interactive communications capability that now
exists in CATV systems. One such interactive communications capability is
that provided by a packet-switched network connection to subscribers via a
modem at the subscriber's location, also known as a cable modem. In
response to packet-switched information being carried on CATV systems, the
CATV network topology typically requires an increased number of spanning
tree networks to provide greater data bandwidth to subscribers by reducing
the total number of subscribers on any one network. Typical systems may
only be able to accommodate between 200-300 subscribers per spanning tree
network. Therefore, a total service area which includes, for example,
10,000 subscribers, may require up to 50 network ports at the head end.
The increased number of network connections at the head end aggravates at
least two problems. First, head end coaxial cables are typically held in
place with threaded connectors, and it is difficult to connect and
disconnect the cables with a wrench if they are in close physical
proximity to each other. The greater the number and density of the
connections, the greater the difficulty is in connecting and disconnecting
them.
Second, to allow for expandability of the network and ease of repair, the
head end typically has multiple electronic modules to which the network
connections are attached. The electronic modules are usually stacked
vertically on top of one another in a rack. If an electronic component in
a module fails, the module may be removed from the system without
affecting the connections of the other modules. However, because the
network connections are attached directly to a module, they must all be
disconnected from the faulty module and reconnected to a new module before
service to subscribers can resume. The necessity of disconnecting and
reconnecting the network connections greatly increases the mean time to
repair (MTTR).
Therefore, there is a need for a way to easily connect network connections
to a head end which allows for system expandability and quick repair.
SUMMARY OF THE INVENTION
The present invention provides a network apparatus having a chassis with an
external network data port and a removable electronic module coupled to
the network data port through an internal data port when the removable
electronic module is present in the chassis. The chassis may also provide
power, radio frequency (RF), data bus, and other types of electrical and
data connections to the electronic module through the use of additional
internal ports. The apparatus may additionally be connected to others via
a data bus, and be included as part of a rack-mounted system. The
electronic module may be inserted and removed from the chassis while
electrical power is applied to the chassis.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is illustrated by way of example and may be better
understood by referring to the following description in conjunction with
the accompanying drawings, in which like references indicate similar
elements and in which:
FIG. 1 shows a front view of preferred stacked network apparatus modules
compatible with the present invention;
FIG. 2 shows an internal view of preferred internal power, data, and RF
ports compatible with the present invention;
FIG. 3 shows a back view of preferred internal power, data, and RF ports
compatible with the present invention;
FIG. 4 shows a side view of a preferred removable network apparatus module
compatible with the present invention;
FIG. 5 shows a front view of preferred stacked network apparatus modules,
in a rack compatible with the present invention;
FIG. 6 shows a perspective view of a preferred network apparatus removable
module compatible with the present invention;
FIG. 7 shows an electrical schematic of a preferred network apparatus
module compatible with the present invention;
FIG. 8A-8C show top views of alternative embodiments of the interface
between external and internal power, data, and RF ports compatible with
the present invention;
FIG. 9A-9C show internal views of alternative embodiments of internal
power, data, and RF ports compatible with the present invention;
FIG. 10A-10C show back views of alternative embodiments of external power,
data, and RF ports compatible with the present invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE PRESENT INVENTION
In the following description of a preferred embodiment, reference is made
to the accompanying drawings which form a part hereof, and in which is
shown by way of illustration a specific embodiment in which the invention
may be practiced. It is to be understood that other embodiments may be
utilized and structural changes may be made without departing from the
scope of the present invention.
The present invention provides for a network apparatus having a chassis
with external network data ports and a removable electronic module coupled
to the network data ports through one or more internal data ports when the
removable electronic module is present in the chassis. The configuration
allows the electronic module to be inserted and removed from the chassis
without connecting and disconnecting the external network data ports. The
electronic module is optionally hot-swappable and may be inserted and
removed from the chassis while electrical power is applied to the chassis.
In addition to data connections, the present invention also provides for
power, radio frequency (RF), data bus, and other types of electrical and
data connections to the electronic module. The present invention is
versatile and is applicable to a wide range of network devices and
applications. The present invention is compatible with rack-mounted
systems which enable incremental scaling of the network. The ability to
insert and remove the electronic module without connecting and
disconnecting the external network data ports greatly reduces the mean
time to repair (MTTR) for the system.
For the purpose of illustration, one embodiment of present invention is
described below in the context of data-over-cable service, also known as
cable modem service. Information and specifications relating to
data-over-cable service are described in the document "Data-Over-Cable
Service Interface Specifications: Radio Frequency Specification",
SP-RFI-I02-9710008, Oct. 8, 1997, Cable Television Laboratories,
Louisville, Colorado, which is incorporated herein by reference. A
communications highway network system for the interactive communication of
digital and analog information that incorporates LAN, MAN and CATV
technology is described by Grobicki et al., "COMMUNICATIONS HIGHWAY
NETWORK SYSTEM", U.S. Pat. No. 5,471,474, issued Nov. 28, 1995, which is
incorporated herein by reference. It will be recognized by one of ordinary
skill in the art that the present invention may be used with other
applications and network devices without loss of generality, such as local
area networks (LANs), wide area networks (WANs), metropolitan area
networks (MANs), plain old telephone service (POTS) modems, packet
switched networks including, but not limited to, transmission control
protocol/internet protocol (TCP/IP) networks, twisted pair and coaxial
cables, optical fiber, and other types of networks and physical
connections.
FIG. 1 shows a front view of a preferred stacked network apparatus 101. A
removable module 103 may preferably be stacked in a vertical configuration
via a rack 105. The front panel 107 of removable module 103 preferably
contains an electronic display 109 which gives status and diagnostic
information about the removable module 103, through any number of means,
including but not limited to light emitting diodes (LEDs), liquid crystal
display (LCD) panels, or other electronic display mechanisms. Optional
user-operated controls for each removable module 103, such as power or
reset controls, may also be located on front panels 107.
FIG. 2 shows an internal view of a preferred stacked network apparatus 101.
The internal panel 201 of network device chassis 211 preferably contains a
power source connector 203 and a power ground connector 205 which provides
electrical power to the network device chassis 211. In a preferred
embodiment relating to data-over-cable service, the power connector 203
connects to an electrical power line of 48 volts and approximately 100
watts, but it will be recognized by one of ordinary skill in the art that
other power connectors and voltages may be used with the present invention
without loss of generality. As described in more detail below, internal
data connector 207 and internal RF connector 209 provide a connection
between external network data, external RF, removable module 103 data and
removable module 103 RF ports when the removable module 103 is present in
the network device chassis 211.
FIG. 3 shows a back view of a preferred stacked network apparatus 101. The
back panel 301 of network device chassis 211 preferably contains one or
more external network data connectors 305, 307 and one or more external RF
connector 303 to provide a connection with an external data network.
Diagnostic information may optionally be displayed through electronic
display means 309, 311. As described in more detail below, external
network data connectors 305, 307 are electronically coupled to one or more
internal data connectors 207, and one or more external RF connector 303 is
electronically coupled to internal RF connector 209.
FIG. 4 shows a side view of a preferred stacked removable network apparatus
module 401. A removable module 103 may preferably be inserted into or
removed from network device chassis 211, either connecting or
disconnecting removable module 103 RF port 403 with internal RF connector
209 (not shown). External RF connector 303 is shown in profile being
attached to the network device chassis 211.
FIG. 5 shows a front view of a preferred stacked network apparatus 501 in a
rack 505. A removable module 503 may preferably be stacked in a vertical
configuration via a rack 505. The front panel 509 of rack connection
module 507 optionally contains connectors 511 for making additional
connections to the system. Electric power is provided to all of the
removable modules 503 in the rack by one or more power supplies 513, 515.
The present invention does not provide any inherent limitation as to how
many modules 503 may be stacked in a rack 505.
FIG. 6 shows a perspective view of a preferred network apparatus removable
module 601. A front panel 603 provides a distal edge, away from the point
of electrical contact, where an electronic display may preferably be
located. A back panel 605 provides a proximal edge, near the point of
electrical contact, where module connectors may preferably be located. The
advantage of this design is that external network cables may be kept out
of sight on the back of the chassis, and diagnostic information may be
displayed on the front of the removable module, which is desirable in many
commercial applications.
FIG. 7 shows an electrical schematic of a preferred network apparatus
module 701. The schematic shows a front edge 703 and electronic display
707, and back edge 705 with module RF connectors 709 and module data
connectors 711, corresponding to the front panel 603 and back panel 605
shown in FIG. 6. It will be recognized by one of ordinary skill in the art
that the electronic connections between external, internal, and module
connectors 709, 711 may vary greatly between embodiments of the present
invention without loss of generality.
FIG. 8A-8C show top views of alternative embodiments of the interface
between external and internal power, data, and RF ports which may be used
with the present invention. A network device chassis 801 preferably
contains a mounting platform 803. The mounting platform 803 may optionally
be a printed circuit board or other platform capable of transmitting
electronic signals. One or more mounting posts or brackets may be one of
many ways to attach the mounting platform 803 to the chassis 801. As shown
in FIG. 8A, internal power source connector 813 and internal power ground
connector 815 may be coupled directly to external power source connector
809 and external power ground connector 811, either through a simple
pass-through configuration or through power line conditioning or
electronics located on the mounting platform 803. External network data
connector 821 may be directly or indirectly electronically coupled to
internal data connector 823. External network RF connector 817 may be
directly or indirectly electronically coupled to internal RF connector
819, shown in FIG. 8A as "D" connector. FIG. 8B shows an alternative
embodiment where the external network RF connectors 825 are coaxial cables
coupled directly or indirectly to internal RF connectors 827. FIG. 8C
shows where external network RF connectors 825 are coaxial cables coupled
to internal RF connector 829, which is a "D" style connector. It will be
recognized by one of ordinary skill in the art that many variations may be
made as to the type and positioning of the internal and external data, RF,
power, and other types of connectors without loss of generality.
FIG. 9A-9C show internal views of alternative embodiments of internal
power, data, and RF ports which may be used with the present invention. A
network device chassis 801 preferably contains a mounting platform 803.
Internal power source connector 813 and internal power ground connector
815 are used to provide power to the electronic module through electronic
module power source and power ground connectors. Internal data connector
823 is used to provide a data connection to a module data connector. FIGS.
9A-9C variously show the internal RF connector either as a "D" style
connector 819, 829, or as coaxial connectors 827.
FIG. 10A-10C show back views of alternative embodiments of external power,
data, and RF ports which may be used with the present invention. A network
device chassis 801 preferably contains external power source connector 809
and external power ground connector 811, which are used to provide power
to the electronic module through electronic module power source and power
ground connectors. External data connector 821 is used to provide a data
connection to a module data connector. FIGS. 10A-10C variously show the
external RF connector either as a "D" style connector 817, or as coaxial
connectors 825.
While the invention is described in terms of preferred embodiments in a
specific system environment, those of ordinary skill in the art will
recognize that the invention can be practiced, with modification, in other
and different hardware and software environments within the spirit and
scope of the appended claims.
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